JDA Tips and Tricks

Overview

This guide gives lists some tips and tricks to ease the life of developers working with JDA, the Discord framework used by this project.

Tips

Use ISnowflake#getIdLong instead of ISnowflake#getId

Internally JDA uses longs instead of Strings, so they are faster and still work.

Example:

long userId = event.getUser().getIdLong();

However, in some cases using long is sub-optimal, for example when comparing it to a component ID. Component IDs are custom strings allowing storing data within the ID. Example:

String userThatClickedId = event.getUser().getId();
String userId = idArgs.get(0);

if (userThatClickedId.equals(userId)) {
    ...
}

If you already have a long, you'll need to cast this to a String resulting in less readable and more code, when JDA can also do this for you internally.

Don't forget .queue();

Almost all Discord requests do not run automatically and require an explicit .queue();.

Affected requests are called RestActions. The rule of thumb is, if your message returns a result it likely has to be queued. Most IDEs can detect such a situation, as seen in the following example:

There are lot of RestAction types

Some of the many RestAction types give you more flexibility and additional functionality.

For example, when editing a message, you can not just add 500 options to the TextChannel#editMessageById() method. Instead, it returns a MessageAction object, which allows you to set all the components and more.

Every JDA related object has a getJDA method

Whenever you need an instance of JDA, the framework got you covered and offers a general getJDA() method available on pretty much any JDA related object.

Cast JDA to JDAImpl for more methods

This is a dangerous tip and we advise you to not consider it unless there is really no other option. If you are unsure, please ask the other developers for help.

Internally JDA uses JDAImpl instead of JDA, which has way more (internal) methods. While almost, if not all, of them are probably not relevant, some might prove useful in very specific use-cases.

Since this is an internal API, breaking changes can happen with any new version of JDA and it also has no documentation.

EntityBuilder (internal)

Note, the entitybuilder isn't meant for serializing and deserializing stored users, it's not backwards compatible.

EntityBuilder is an internal class of JDA used to create Discord entities (users, guilds, and more) from their JSON value (DataObject's). Within the TJ-Bot we make usage of this to test command's their logic.

By creating "fake" JSON's we can make create an event, members and such using an EntityBuilder. A.e the EntityBuilder#createUser method.

To be more precise, you can view the createUser method here. If we'd give the createUser method a DataObject with the following JSON. We'd be able to make JDA think Nelly is a real user. For an up-to-date example, check the Discord docs

/* 
  Note: this json is from 13/10/2021 
  This might be changed at the moment of reading
*/
{
  "id": "80351110224678912",
  "username": "Nelly",
  "discriminator": "1337",
  "avatar": "8342729096ea3675442027381ff50dfe",
  "verified": true,
  "email": "[email protected]",
  "flags": 64,
  "banner": "06c16474723fe537c283b8efa61a30c8",
  "accent_color": 16711680,
  "premium_type": 1,
  "public_flags": 64
}

Tricks

Due to the complexity of JDA, you might easily run into a situation where you solve a problem in a certain but not optimal way that is either overly complex or just very lengthy. This chapter shows some tricks to help you use JDA correct and better.

Method shortcuts

JDA offers some shortcuts to methods and patterns frequently used:

• JDA#openPrivateChannelById, instead of manually retrieving the user and calling User#openPrivateChannel
• JDA#getGuildChannelById also applies to textchannels, storechannels and more. So a Guild instance is not required to get channels.

Raw events

In case you need to inspect an event send by Discord or JDA closely in its raw JSON form, one can enable raw events and inspect the payloads:

// where the JDA instance is created
JDA jda = JDABuilder.createDefault(...)
  .setRawEventsEnabled(true) // add this call
  ...
  .build();

// and then add a raw event listener
jda.addEventListener((EventListener) event -> {
  if (event instanceof RawGatewayEvent rawEvent) {
    System.out.println(rawEvent.getPayload());
  }
});